Adjustable baffle for paper stock inlet



Feb. 22, 1966 P. H. GOLDSMITH ADJUSTABLE BAFFLE FOR PAPER STOCK INLET 3Sheets-Sheet 1 Filed March 18. 1963 INI'ENTOR Philip H. GOLDSMITHggfgwfarzfiaay C;

Feb. 22, 1966 P. H. GOLDSMITH 3,236,725

ADJUSTABLE BAFFLE FOR PAPER STOCK INLET Filed March 18, 1963 5Sheets-Sheet 2 INVENTOR Philip H. GOLDSMITH A TTORNE Y5 Feb. 22, 1966 P.H. GOLDSMITH 3,236,725

ADJUSTABLE BAFFLE FOR PAPER STOCK INLET Filed March 18, 1963 5Sheets-Sheet 3 25 4- 58 35 O y Y 4 x M 54 J in I 40 l' /4 IH INVENTORPhili H. GOLDSMITH A TTORNE YS United States Patent C 3,236,725ADJUSTABLE BAFFLE FOR PAPER STOCK INLET Philip H. Goldsmith, Montreal,Quebec, Canada, assignor to Dominion Engineering Works Limited,Montreal, Quebec, Canada Filed Mar. 18, 1963, Ser. No. 265,711 Claimspriority, application Canada, Feb. 9, 1963, 868,470 6 Claims. (Cl.162336) This invention relates to paper making machine stock inlets andmore particularly to an adjustable flexible baffle device positioned ina stock inlet to produce a flow of paper stock, from the stock inlet,which is of stable and uniform velocity, is of uniform fibre dispersionand is free from large patterns of turbulence, on to a conventionaldrainage unit such as, a Fourdrinier, a cylinder paper or board machine,a thickener, etc.

To manufacture a sheet of paper of uniform weight, it is necessary thatthe flow of dilute paper stock, across the width of the machine, be of astable and uniform velocity and have uniform dispersion of fibres. It isalso very important that large patterns of turbulence do not occur inflow, since these disturbances will create defects in the formation ofthe sheet.

The essential features of this invention lie in the provision of aflexible baffle device which, positioned in a headbox stock inletchamber between the distributor and slice or stock outlet, produces aflow of paper stock with the aforementioned desirable characteristics.

Baflles of various types have long been used in paper making machineheadboxes, to suppress large patterns of turbulence and to produce amore uniform flow of stock.

In open type headboxes, rigid baffle plates, usually verticallypositioned in the headboxes, are arranged in slides and adapted to bemoved up and down within the slides to provide an opening, of adjustablewidth, through which the stock flows.

This arrangement has not proved to be too satisfactory because themechanism rapidly becomes inoperative due to corrosion and to thecollection of stock fibres in the slides. The collection of stock fibresin the slides not only causes the mechanism to become inoperative, but

'also results in the formation of lumps of paper stock, in

the vicinity of the slides, which break loose and contaminate the stockflow to produce an unsatisfactory sheet of paper.

In high and wide open type headboxes these conventional baflles producea further disadvantage in that the baffle plates become excessivelyheavy and unwieldly and provide difliculties in handling,

In inclosed pressure type headboxes, it is diificult and objectionableto incorporate adjustable rigid baffle plates, for the suppression oflarge patterns of turbulence.

One arrangement of pressure type headbox has provided an adjustableopening, between the stock flow distributor and the inlet chamber, bythe raising and lowering of a heavy back plate which forms part of theheadbox structure.

This arrangement is very inconvenient to operate, requiring that thepaper machine to be shut down in order to reposition the back plate tochange the width of the opening.

Another arrangement of pressure type headbox incorporates a rotarybaflle positioned in the stream of stock within the headbox.

This arrangement of rotary baflle is also not too satisfactory, becausetwo channels of stock flow are created around the baflle, resulting in acoarser pattern of turbulence.

The baffle device disclosed herein comprises one or more flexible baflleplates extending across the stock inlet chamber in a directiontransverse to the stream of stock flowing through the inlet chamber, thebaflle plates being securely anchored along one longitudinal edge to thestock inlet and adjustably flexible about the anchored edge, in thedirection of stock flow, to produce a turbulence suppressing restrictionin the stock flow path.

The stream of stock which flows around the baflle plate reverses itsdirection of flow and doubles back on itself, thus providing that stockof the same consistency, and with very little pressure difference, ispresent on both sides of the baflle plate. Therefore, the ends of thebaffle plate do not have to be sealed to the sides of the inlet chamberand in practice, a clearance of about can be left at each end of thebaffle plate, thus eliminating all difficulties inherent in theconventional baffle plate arrangements, due to accretions of stock inthe slides, etc. Thus a stream of stock will flow around each end of thebafile plate and provide a self cleaning action.

In the disclosed preferred execution, the free longitudinal edge of thebaflle late is formed as a bulbous shaped lip to provide structural edgestiffness and maintain a consistent velocity profile of the stock flow.

An additional feature of the bulbous lip is the promotion of improvedstock flow characteristics around the stream-lined baflle edge, thusdiscouraging the development of large patterns of turbulence in theflow.

The flexible baffle plate, or plates, are adapted at their ends to beadjustably clamped to the inlet chamber sides, in a manner whereby theposition of the baffle plates may be adjusted, and their positionsnoted, from outside the headbox.

It is, therefore, the main object of this invention to provide aflexible baffle device, positioned in an inlet chamber between a paperstock flow distributor and a conventional drainage unit, which willproduce a flow of paper stock from the inlet chamber, which is of stableand uniform velocity, is of uniform fibre dispersion and is free fromlarge patterns of turbulence.

Another object is to provide a flexible baffle device, positioned in aheadbox, which is quickly adjustable from outside the headbox whilst themachine is in operation, so that the results of adjustments made may beimmediately observed at various positions on the paper machine beyondthe headbox, and further adjustments made where necessary to providestock flow with the characteristics described in the aforementionedobjective, for various operating conditions.

Another object is to provide a baflle device which is of flexibleconstruction, thereby eliminating all mechanical joints.

Another object is to provide an adjustable flexible baffle device inwhich, a clearance is maintained between each end of the baflle deviceand the stock inlet chamber side walls, thus eliminating all baflle endseals, slides, etc., and providing a self-cleaning action, due to theflow of stock around the baflle ends.

Another object is to provide an adjustable flexible baflle device whichmay be positioned in a headbox with little or no increase in the lengthof the headbox in the machine length direction.

A further object is to provide a flexible baffle device, positioned in astock inlet chamber, which is of simple construction and thus simplifiesroutine clean-out operations.

These and other objects of this invention will be apparent from thefollowing specification and the accompanying figures in which similarreference numerals refer to similar parts throughout.

In the following specification:

FIG. 1 is a sectional view through a typical enclosed pressure typeheadbox, embodying one execution of this invention in which two flexiblebaflle plates are vertically arranged in the stock inlet chamber.

FIG. 2 is a partial sectional view, similar to FIG. 1, but embodyinganother execution of this invention in which one flexible baflie plateis vertically arranged in the stock inlet chamber.

FIG. 3 is a partial sectional view, similar to FIG. 1, embodying anotherexecution of this invention in which two flexible baffle plates arehorizontally arranged in the stock inlet chamber.

FIG. 4 is a partial sectional view, similar to FIG. 1, embodying afurther execution of this invention in which one flexible baflle plateis horizontally arranged in the stock inlet chamber.

FIG. 5 is a partial sectional view taken in the direction of 5-5 in FIG.2.

FIG. 6 is a view, to an enlarged scale, taken in the direction of arrow6 in FIG. 5, showing details of the means for clamping the baffle plateto the stock inlet side walls.

FIG. 7 is a section on 77 in FIG. 6.

FIG. 8 is a section on 8-8 in FIG. 6.

With reference now to FIG. 1, stock distributor 11 is attached to stockinlet chamber 12 of typical pressure type headbox 13 and positioned ininlet chamber 12 are flexible bafl les 14 extending across inlet chamber12 transverse to the direction of stock flow. One of the flexiblebaffles 14 is positioned vertically and rigidly attached at its loweredge to the lower surface of the inlet chamber 12, the upper edge havingthe form of a bulbous lip 15, and the other flexible baffie 14 beingpositioned vertically, but inverted, and rigidly attached at its upperedge to the upper surface of inlet chamber 12, the lower edge alsohaving the form of a bulbous lip 15.

In this execution, the two baffles 14 are adjustable to form twoturbulence suppressing restrictions at 16 and 17 with a turbulencechamber 18 formed therebetween. The upper part of turbulence chamber 18is vented to the main headbox chamber 19 by vents 20, to preventaccumulation of air.

Thus stock entering the headbox will flow from distributor 11, through adouble U path formed by baffle restriction 16, turbulence chamber 18 andbaffle restriction 17, through the main headbox chamber 19 and outthrough slice 21 on to the Fourdrinier drainage wire 22.

Reference now to FIG. 2 shows another execution in which only oneflexible baffle 14 used, being positioned vertically and rigidlyattached to the lower surface of inlet chamber 12. In this execution, arigid baflie plate 23 extends downwardly from the upper surface of inletchamber 12, to provide a double U flow path for the stock to travel,similar to the flow path shown in FIG. 1. In this execution there isonly one baflie restriction 18. Vents 20 are again provided to vent theupper part of inlet chamber 12 to the main headbox chamber 19, toprevent accumulation of air.

Reference to FIG. 3 now, shows another execution in which two flexiblebaffles 14 are positioned in inlet chamber 12, but in this executionthey are positioned substantially horizontally and securely anchored toeach of the side walls of inlet chamber 12, to again form a double Uflow path, through which the stock will travel. In this execution, theupper surface of inlet chamber 12 is upwardly sloped to prevent anyaccumulation of air. Also, flexible baffles 14 have an upwardly slopedbias and are arranged to be upwardly adjustable, to again preventaccumulation of air.

Reference now to FIG. 4 shows a further execution of this invention inwhich only one flexible baffle 14 is positioned substantially horizontalin inlet chamber 12 surface of inlet chamber 12 is upwardly sloped toprevent any accumulation of air.

FIG. 5 is a sectional view taken on 55 in FIG. 2 and shows an end viewof flexible baffie 14, with end clearances 24 and vents 20 and showingthe bafile journals 25 extending through both side walls of inletchamber 12.

FIG. 6 is a view, to an enlarged scale, taken in the direction of arrow6 in FIG. 5 and is typical for both ends of flexible baffle 14, showingflexible baffle 14 vertically positioned and securely attached at 26 tothe lower surface 27 of inlet chamber 12.

Reference now to FIGS. 6, 7 and 8 shows details of a conventional meansfor adjusting and clamping flexible baffle 14 to the side walls of inletchamber 12.

Baflie journals 25 are securely attached to the end plates 28 offlexible bafiles 14, and extend through slots 29 in the side walls ofinlet chamber 12. Cover plates 30 are positioned between end plates 28and the inside surfaces of the end walls of inlet chamber 12 andarranged so that slots 29 are always covered, throughout the range ofbaflie adjustment, to prevent leakage of stock. Cover plate sleeves 31are attached to cover plates 30, project through slots 29 and are boredto provide a close sliding fit on baffle journals 25.

Head ends 32, of adjusting screws 33, are bored to provide a sliding fiton sleeves 31 and are secured thereon by nuts 34, screwed to threadedportions on the ends of sleeves 31. It will be noted, in FIG. 7, thatwhen nuts 34 are tightened, cover plates 30 are pulled up hard againstthe inside surfaces of the end walls of inlet chamber 12 and head ends32 are jammed against the outside surfaces of said end walls, thustightly sealing slots 29 and securely positioned baflle journals 25 andflexible baffle 14.

Adjusting screws 33 are located in bores 35 in supporting lugs 36.Supporting lugs 36 project at right angles from reinforcing plates 37,which are welded or otherwise attached to the outer surfaces of the endwalls of inlet chamber 12.

Adjusting nuts 38 are assembled on adjusting screws 33 and are held inspaced relation to supporting lugs 36 by spherical collars 39. Sphericalcollars 39 have flat inner surfaces abutting flat end surfaces ofadjusting nuts 38, and spherical outer surfaces located in sphericaldepressions on the insides of bores 35 in supporting lugs 36, thusproviding for smooth rotation of adjusting nuts 38 on adjusting screws33, throughout the range of baflie adjustment.

Ratchets 40 are provided for convenient adjustment of adjusting nuts 38.

Scales 41 are provided on slots 29, to enable each end of flexiblebaflle 14 to be adjusted and aligned as required.

Thus, flexible baflies 14 can be quickly adjusted by slackening nuts 34,operating ratchets 40 until the desired baffle positions are indicatedon scales 41, and then retightening nuts 34.

It will be understood that, although these executions have beendescribed as embodying separate adjusting arrangements for each end offlexible baffles 14, conventional arrangements could be utilized topermit all adjustments, to the flexible baffles, to be made from oneside of the headbox. This arrangement would be especially useful whenapplied to flexible baflles installed in narrow headboxes.

Routine cleaning of the flexible bafiles can be readily carried outthrough washout doors installed at each end of the inlet chamber.

It will be seen from the foregoing specification that flexible bafiles,according to this invention, installed in paper machine stock inlets,provide a simple and eflicient means for suppressing large patterns ofturbulence and thus providing a uniform flow of stock on to a drainageunit. As will also be seen, flexible baflies, providing stock flow withthe above mentioned desirable characteristics, may be installed in papermaking machine headboxes with little or no increase in headbox size, inthe machine length direction.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a stock feeding apparatus for paper making machines comprising aheadbox and a stock distributor through which stock is introduced intothe hcadbox the improvement comprising (a) a stock inlet chamber tocommunicate the stock distributor with the headbox (b) at least oneflexible baflie located within said inlet chamher, said baflie havingtwo longitudinal edges one of which is rigidly attached to a wall ofsaid inlet chamber, said bafiie being flexible so as to be disposable ina plurality of positions of adjustment and (0) means for securing thebatfle in any selected one of the plurality of positions of adjustment.

2. A stock feeding apparatus as in claim 1 wherein at least one saidflexible batfle has along the longitudinal edge opposite said attachedlongitudinal edge a bulbous lip reinforcement.

3. A stock feeding apparatus as in claim 1 wherein at least one saidflexible baffle is disposed in spaced opposing relation to another wallof the inlet chamber to form with the latter a restricted passage insaid inlet chamber through which stock passes from distributor into theheadbox, the said positions of adjustment controlling the width of saidpassage.

4. A stock feeding apparatus as in claim 1 wherein at least one saidbaflle is positioned vertically and rigidly attached at its lowerlongitudinal edge to the lower wall of the inlet chamber.

5. A stock feeding apparatus as in claim 1 wherein there are twobaflles, a first flexible baflie positioned vertically and rigidlyattached at its lower longitudinal edge to the lower wall of the inletchamber and a second baffle positioned vertically and rigidly attachedat its upper longitudinal edge to the upper wall of said inlet chamberso as to form a double U stock fl'ow path.

6. A stock feeding apparatus as in claim 1 wherein at least one saidflexible baflie is positioned substantially horizontally and rigidlyattached at one of the longitudinal edges to a vertical wall of theinlet chamber.

References Cited by the Examiner UNITED STATES PATENTS 2,005,839 6/1935Edge .....1 l6 2323 2,046,270 6/1936 Lane et al 162-318 2,200,002 5/1940Lane et al l623 18 2,688,277 9/1954 Luebke 162-343 2,854,895 10/1958Cirrito 162337 3,021,899 2/ 196 2 Goldsmith 162--327 3,034,577 5/1962Cirrito 162-337 DONALL H. SYLVESTER, Primary Examiner.

1. IN A STOCK FEEDING APPARATUS FOR PAPER MAKING MACHINES COMPRISING AHEADBOX AND A STOCK DISTRIBUTOR THROUGH WHICH STOCK IS INTRODUCED INTOTHE HEADBOX THE IMPROVEMENT COMPRISING (A) A STOCK INLET CHAMBER TOCOMMUNICATE THE STOCK DISTRIBUTOR WITH THE HEADBOX (B) AT LEAST ONEFLEXIBLE BAFFLE LOCATED WITHIN SAID INLET CHAMBER, SAID BAFFLE HAVINGTWO LONGITUDINAL EDGES ONE OF WHICH IS RIGIDLY ATTACHED TO A WALL OFSAID INLET CHAMBER, SAID BAFFLE BEING FLEXIBLE SO AS TO BE DISPOSABLE INA PLURALITY OF POSITIONS OF ADJUSTMENT AND (C) MEANS FOR SECURING THEBAFFLE IN ANY SELECTED ONE OF THE PLURALITY OF POSITIONS OF ADJUSTMENT.